Ultra fine colloid mill

ABSTRACT

A colloid mill is characterized by a stator and a rotor disposed along an axis. The stator has a re-entrant conical surface with grooves extending from the outer periphery to an inner axial opening. The rotor is keyed to a shaft that extends through the axial opening of the stator and has vanes with outer edges that are closely adjacent to and in registration with the conical surface of the stator. The arrangement is such that the high speed rotation of the rotor causes fragmentation of colloid particles in a fluid that is driven under pressure from an inlet through the small clearance between the conical surface of the stator and the vanes of the rotor and through the clearance between the axial opening of the stator and the shaft of the rotor.

United States Patent 1191 1111 3,788,565 Adams 51 Jan. 29, 1974 ULTRA FINE COLLOID MILL Primary Examiner-Granville Y. Custer, Jr. [75] Inventor: Robert R Adams, Hudson NY 'Attorney, Agent, or Firm-Gerald Altman et a1. [73] Assignee: Columbia Precision Corporation,

New York, NY. ABSTRACT [22] Filed; F b, 2, 1972 A colloid mill is characterized by a stator and a rotor disposed along an axis. The stator has a re-entrant [21'] conical surface with grooves extending from the outer periphery to an inner axial opening. The rotor is keyed 52 US. Cl 241/46.11, 241/163, 241/261.3 to a shaft that extends through axial Opening of the [51] Int. Cl. B02c 21/00 Stator and has vanes with Outer edges that are Closely 53 Field f Search 241 43 45 4 4 11 adjacent to and in registration with the conical surface 241/4617, 155, 161, 162, 163, 244, 260, of the stator. The arrangement is such that the high I 2611,2613 speed rotation of the rotor causes fragmentation of v colloid particles in a fluid that is driven under pressure [56] References Cited from an inlet through the small clearance between the U I E STATES EN conical surface of the stator and the vanes of the rotor 3 224 689 12/1965 Behrens at a] 241/244 and through the clearance between the axial opening 2:697:966 12/1954 Hyman QIII IIII 241 261.1 of the Stat and the Shaft Qfthe 267,768 11/1882 Bailey et aL... 241/43 2,362,035 11 1944 Sullivan 241/244 x 16 Clam, m 3,008,505 11/1961 Pavia 241/162 X 3,514,079 5/1970 Little, Jr. 24l/26l.l X

PATENTEU JAN29 23M SHEU 1 OF 4 d 1 ULTRA FINE COLLOID MILL BACKGROUND AND SUMMARY The present invention relates to colloid mills and, more particularly, to colloid mills capable of producing ultra fine colloids. Conventional colloid mills have been usedto produce emulsions characterized by particle sizes ranging from submicron to one or two microns. Typically, liquid is refined by passage through anadjustable gap between a solid rotor and af solid stator. If the gap is too narrow, the material will not feed. If the gap is too wide the degree of refinement-is not adequate.

The primary'object of the present invention is to provide a colloid mill, in which the liquid being refined is characterized by an interface between the rotor and the stator. On one side of the interface, the liquid is retained by the adjacent face of the'stator in stationary position. On the other side of the interface, the liquid is retained by theiadjacent face of the rotor for movement with respect to the stator. The result, in effect, in-

volves liquid stator and rotor faces, which enablecontinuous feeding but between which is no gap. Specifically, the stator has a resentrant conical surface with grooves extending from the outer periphery to an inner axial opening. The rotor is; keyed to a'shaft that extends through the axial opening of the stator and has vanes with outer edges thatare closely adjacent to and inreg istra'tion with the conical surface of the stator. The grooves tend to retain liquid in contiguity with the stator relatively stationary. The'vanes tend to carry liquid in contiguity with the rotor for movement with respect to the stator; The arrangement is such that colloid par-' ticles in a fluid,advancin'g from an inlet to an outlet, are unusually effectively fragmented down to sizes that characteristically maybe as .small as one-tenth of a micron.

Other objectslof'the present invention will in part be obvious and will in part appear hereinaften.

The invention accordingly comprises the apparatus, and process together with their components, steps and interrelationships, which are exemplified in the present disclosure, the scope of which will be indicated in the appended claims.

BRIEF DESCRIPTION or THE DRAWINGS For a fuller understanding of the nature and objects FIG. 1 taken substantially along the line 2-'2 of FIG.

shown in-FIG. 2, the view being taken substantially along the line 3.'-3 of FIG. 2;

FIG. 4 is an end view, of armor of the apparatus of FIG. '2,'the view with components omitted being taken substantially along the line-4-4 of FIG. 2;

FIG. .5 is a cross. sectional view of a stator of the apparatus of FIG. 1, the cross section being taken at the axis of the apparatus; I

FIG. 6 is an end view of the stator of FIG. 5;

FIG. 3 is an end view or. the head of the apparatus.

FIG. 7 is a side elevation of a complete apparatus in which a colloid mill, of the type shown in FIG. I, is a DETAILED DESCRIPTION 7 a dispersion having a liquid outer phase is fed for the purpose of refinement between an inlet port 24 and an outlet port 26. Housing 20 includes five aligned, centrally opened disks, which are flush peripherally in order to define an outer cylindrical surface. These disks include an inletring 28, a first stator ring 30, a second stator ring 32, an'outlet ring 38 and a sealing ring 40. Each preceding ring is seated'on the succeeding ring by means of a peripheral shoulder recess 42 in the inner surface of the preceding ring and aperipheral shoulder ledge 44in the outer surface of the succeeding ring. Also adjacent ringsare hermetically sealed by groove and O-ring arrangements 46.

Stators 30and 32 each provides a re-entrant conical face 48 having a central aperture 50. Conical face 48 is provided with: grooves 52, which extend froma position adjacent to the outer periphery of conical face 48 to a position adjacentto central aperature 50; and grooves 53, which are T-shaped and which extend from a T-head, that is'positioned between the outer periphery of the conical surface and the'inner aperture, to selected ones of a series of parallel grooves 36 in the face of aperture 50. Y

Rotatable within the regions defined by conical faces 48 of rings 30, 32 are rotors 55, 57 each of which provides a series of six vanes 56, FIG. 4, the outer edges 58 of which are in close adjacency with conical surface 48. Edges 58 are disposed along a theoretical conical surface that is closely spaced to the surface 48 of the stator.

Extending rearwardly from sealing ring 40 is a bearing housing 60. Each rotor 55, 57 is keyed to the free end of a shaft 62. Shaft 62 is driven at its other end 64, which extends through bearing housing 60, where it is joumaled in two ball bearing units 66, 68. Shaft 62 extends through the central opening in sealing disk 40, through the collecting I cavity of outlet 'disk 38, and

through the refining regions encompassed by stators- 32, 30, within which rotors 55, 57 are carried by shaft 62. The free end of shaft 62 extends into the cavity of ring 30in cantilever fashion. As shown, stators32 and 30, have a central bore through which shaft 62 projects. As shown, the shank 65 of rotor 57 abuts against the shank 67 of rotor 55 and the shank 67 of rotor 55 abuts against a shoulder 70 of shaft 62. The rotors are locked into their positions on shaft 62 by a retainer ring 74 which is clamped against shank 65 of rotor 57 by a nut 76, which is turned onto a threaded stub of shaft 62.

As shown in FIG. 2, bearing housing 60 is fastened, by webs 61 to sealingring 40. Rings 40, 38, 32, 30, 28 are tied together by bolts 82 (one shown in FIG. 2) that extend through aligned bores in the rings, opposite threaded ends of the bolts being meshed with nuts 84, 86. As shown in FIG. 3, there are eight such nut and bolt ties. As best shown in FIG. 2, O-ring at 90 and seals at 92, and 94 hermetically isolate the bearing housing from the atmosphere. Mechanical seal 34 and O-ring 88 seal the milling cavity 22 from the atmosphere. Seals 96, 98 create a chamber behind mechanical seal 34 for the introduction of a flush fluid to protect seal 34. A

gravity feed lubricant supply 100 communicates with the shaft through a bore 102 in sealing ring 40.

As shown in FIG. 4, each of rotors 55, 57 has six vanes 56, each of which is disposed along a plane that is offset from and parallel to a line radially through the axis of rotation. The lines of orientation of blades 56 and the lines of orientation of grooves 52, 53 are arranged so that as the blades spin, the lines are parallel, thereby creating rapid pressure changes within the grooves. The centrifugal force created by the revolving turbine blades 56 imparts velocity to the fluid thereby pumping fluid from inlet 24, through cavity 22 and through outlet 26. As shown in FIG. and 6, each stator is provided with a cylindrical outer periphery 104 having a plurality of grooves 106, each of which opens at the outer extremity of the cylindrical surface of revolution and defines a point at the inner extremity of the cylindrical surface of revolution.

OPERATION In operation, the cylindrical surfaces of revolution of the stator and rotor are coated with fluid layers that contact each other but that move with respect to each other. The result is an extremely high shear gradient at the interface between the moving and stationary fluid layers. The arrangement is such that the direction of flow of the refined material is counter to the centrifugal force. As a result, back pressure and retention time are increased to produce more work in the fluid.

FIGS. 7 and 8 illustrate an arrangement of apparatus within which the colloid mill of FIG. 1 is incorporated. As shown in FIG. 7, this colloid mill is shown at 110 as having a transmission 112 which is driven through a pulley 114 by an endless belt 1 16 and a pulley 118 that is keyed to the shaft of a motor 120. In this arrangement as shown in FIG. 8, motor 120 is supported within a frame 122 on a cross plate 124 and colloid mill 110 is supported above it on a cross piece 126. An alternative embodyment is shown in FIGS. 9 and 10, wherein a colloid mill 128 is driven through a pulley 130, a belt 132 and a pulley 134 by a motor 136, which is mounted upon a base 138 that also supports colloid mill 128.

The present invention thus provides an improved colloid mill capable of producing ultra fine colloid particles. In operation the unit is belt driven to produce speeds of 3,550 to 4,550 revolutions per minute. At 4,550 revolutions per minute, the peripheral velocity of the blade tip is 160 feet per second. As a result fluid enters inlet 24 and flows then thorugh the first subchamber in which rotor '57 operates, next through the second sub-chamber in which rotor.55 operates, then through the third sub-chamber which communicates with outlet 26, from which the ultra-refined liquid is released.

Since certain changes may be made in the foregoing disclosure, without departing from the'scope of the invention herein, it is intended that all matter shown in the accompanying drawings and described in the foregoing specification be interpreted in an illustrative and not in a limiting sense. 1

What is claimed is:

l. A colloid Mill comprising a casing disposed along an axis, a shaft disposed for rotation along said axis within said casing, at least a stator disposed about said shaft, said stator defining a re-entrant conical surface of revolution, and a re-entrant cylindrical surface of revolution in communication with each other said-sun faces having therein grooves, a first series of said grooves extending from the forward periphery of said re-entrant conical surface to a medial portion thereof, a second series of said grooves extending from a medial portion of said re-entrant conical surface to the rearward periphery thereof, said first series of said grooves and said second series of said grooves being isolated from eachother, at least a rotor keyed to said shaft for rotation therewith, said rotor having spaced baldes, the outer edges of said blades being disposed in a conical surface of revolution, said concial surface of any stator and said conical surface of any rotor being adjacent, rotation of said rotor causing refinement of colloid particles in a fluid passing from an inlet at one extremity of said shaft through at least a chamber defined by said stator and within which said rotor rotates, between said conical surfaces and through an outlet that is disposed in an axis perpendicular to the axis of said shaft.

2. The colloid mill of claim 1 wherein said conical surface of said stator and said conical surface of said rotor are spaced at most .01 inch from each other.

3. The colloid mill of claim 1 wherein, in sequence, there are a plurality of stators, a plurality of rotors and a plurality of chambers.

4. The colloid mill of claim 1 wherein one portion of said shaft is joumaled for rotation and the portion of said shaft within said chamber extends to a free extremity thereof.

5. The colloid mill of claim 1 wherein said slots include a first series of slots extending from a point adjacent to the outer periphery of said conical surface of said stator to a point adjacent to the inner aperture of said conical surface of said stator.

6. A colloid mill comprising a casing disposed along an axis, a shaft disposed for rotation along said axis within said casing, at least a stator disposed about said shaft, said stator defining a re-entrant conical surface of revolution, said surface having therein grooves, at least a rotor keyed to said shaft for rotation therewith, said rotor having spaced blades, the outer edges of said blades being disposed in a conical surface of revolution, said conical surface of any stator and said conical surface of any rotor being adjacent, rotation of rotor causing refinement of colloid particles in a fluid passing from an inlet at one extremity of said shaft through at least a chamber defined by said stator and within which said rotor rotates, between said conical surfaces and through an outlet that is disposed in an axis perpendicular to the axis of said shaft, one of said series of said grooves extending from a T-head medially located between the outer periphery of said conical surface of said stator and the inner aperture of said conical surface of said stator to a point communicating with said inner'aperture of said stator.

7. The colloid mill of claim 1 including an inlet ring defining said inlet, a stator ring defining said reentrant conical surface and an outlet ring defining said outlet, the outer peripheries of said inlet ring, said stator ring, and said outlet ring being of like circular cross section and being registered to define an outer cylinder.

8. A colloid mill comprising a casing disposed along an axis, said casing including a plurality of aligned rings, a shaft disposed for rotation along said axis within said casing, one of said rings defining a stator disposed about said shaft, said stator defining a reentrant conical surfaceof revolution, and a re-entrant tubular surface of revolution in communication with eachother, said surfaces having therein grooves, a first series of said grooves extending from the forward periphery of said re-entrant conical surface to a medial portion thereof, a second series of said grooves extending from a medial portion of said re-entrant conical surface to the rearward periphery thereof, said first series of said grooves and said second series of said grooves being isolated from eachother, at least a rotor keyed to said shaft for rotation therewith, said rotor having spaced blades, the outer edges of said blades being dis-- posed in a conicalsurface of revolution, said conical surface of any stator and said conical surface of any rotor being adjacent, another of said rings defining an inlet and another of said rings defining an outlet, rotation of rotor causing refinement of colloid particles in a fluid passing from said inlet at one extremity of said shaft through at least a chamber defined by said stator and within which said rotor rotates, between said conical surfaces and through said outlet.

9. The colloid mill of claim 8 wherein said conical surface of said stator and said conical surface of said rotor are spaced at most 0.01 inch from each other.

10. The colloid mill of claim 8 wherein, in sequence,

there are a pluralityof stators, a plurality of rotors and a plurality of chambers. 11. The colloid mill of claim 8 wherein one portion of said shaft is journaled for rotation and the portion of said shaft within said chamber extends to a free extremity thereof.

12. The colloid mill of claim 8 wherein said slots include a first series of slots extending from a point adjacent to the-outer periphery of said conical surface of said stator to a point adjacent to the inner aperture of said conical surface of said stator.

13. A colloid mill comprising a casing disposed along an axis, said casing including a plurality of aligned rings a shaft'disposed for rotation along said axis within said casing, one of said rings defining a stator disposed about said shaft, said stator defining a re-entrant conical surface of revolution, said surface having therein grooves, at least a rotor keyed to said shaft for rotation therewith, said rotor having spaced blades, the outer edges of said blades being disposed in a conical surface of revolution, said conical surface of any stator and said conicalsurface of any-rotor being adjacent, another of said rings defining an inlet and another of said rings defining an outlet, rotation of rotor causing refinement of colloid particles in a fluid passing form said inlet at one extremity of said shaft -through at least a chamber defined by said stator and within which said rotor rotates, between said conical surfaces and through said outlet, one of said series of said grooves extending from a T- head medially located between the outer periphery of said conical surface of said stator and the inner aperture of said conical surface of said stator to a point communicating with said inner aperture of said stator.

14. A colloid mill comprising a casing disposed along an axis, said casing including a plurality of aligned rings, a shaft disposed for rotation along said axis within said casing, a plurality of said rings defining a plurality of stators disposed about said shaft, said stators defining reentrant conical surfaces of revolution,

' and re-entrant tubular surfaces of revolution said surfaces each having therein grooves, a first series of said grooves extending from the forward periphery of one of said re-entrantconical surfaces to a medial portion thereof, a second series of said grooves extending from a medial portion of said one of said re-entrant conical surfaces to the rearward periphery thereof, said first series of said grooves and said second series of said grooves being isolated from eachother, a plurality of rotors keyed to said shaft for rotation therewith, each said rotor having spaced blades, the outer edges of said blades being disposed in a conical surface of revolution, said conical surface of any stator and said conical surface of any rotor being adjacent, another of said rings defining an inlet and another of said rings defining an outlet, rotation of rotor causing refinement of colloid particles in a fluid passing form said inlet at one extremity of said shaft through at least a chamber defined by said stator and within which said rotor rotates, between said conical surfaces and through said outlet said conical surface of said stator and said conical surface of said'rotor are spaced at most .01 inch from each other, one portion of said shaft being joumaled for rotation and the portions of said shaft keyed to said rotors extending to a free extremity thereof.

15. The colloid mill of claim 14 wherein said slots include a first series of slots extending from a point adjacent to the outer periphery of said conical surface of said stator to a point adjacent to the inner aperture of said conical surface of said stator.

16. A colloid mill comprising a casing disposed along an axis, said casing including a plurality of aligned rings, a shaft disposed for rotation along said axis within said casing, a plurality of said rings defining a plurality of stators disposed about said shaft, said stators defining re-entrant conical surfaces of revolution, said surfaces each having therein grooves, a plurality of rotors keyed to said shaft for rotation therewith each said rotor having spaced blades, the outer edges of said blades being disposed in a conical surface of revolution, said conical surface of any stator and said conical surface of any rotor being adjacent, another of said rings defining an inlet and another of said rings defining an outlet, rotation of rotor causing refinement of colloid particles in a fluid passing from said inlet at one extremity of said shaft through at least a chamber defined by said stator and within which said rotor rotates, between said conical surfaces and through said outlet said conical surface of said stator and said conical surface of said rotor are spaced at most .01 inch from each other, one portion of said shaft being journaled for rotation and the portions of said shaft keyed to said rotors extending to a free extremity thereof, one of said series of said grooves extending from a T-head medially located between the outer periphery of said conical surface of said stator and the inner aperature of said conical surface of said stator to a point communicating with said inner aperture of said stator. 

1. A colloid Mill comprising a casing disposed along an axis, a shaft disposed for rotation along said axis within said casing, at least a stator disposed about said shaft, said stator defining a re-entrant conical surface of revolution, and a re-entrant cylindrical surface of revolution in communication with each other said surfaces having therein grooves, a first series of said grooves extending from the forward periphery of said reentrant conical surface to a medial portion thereof, a second series of said grooves extending from a medial portion of said re-entrant conical surface to the rearward periphery thereof, saiD first series of said grooves and said second series of said grooves being isolated from eachother, at least a rotor keyed to said shaft for rotation therewith, said rotor having spaced baldes, the outer edges of said blades being disposed in a conical surface of revolution, said concial surface of any stator and said conical surface of any rotor being adjacent, rotation of said rotor causing refinement of colloid particles in a fluid passing from an inlet at one extremity of said shaft through at least a chamber defined by said stator and within which said rotor rotates, between said conical surfaces and through an outlet that is disposed in an axis perpendicular to the axis of said shaft.
 2. The colloid mill of claim 1 wherein said conical surface of said stator and said conical surface of said rotor are spaced at most .01 inch from each other.
 3. The colloid mill of claim 1 wherein, in sequence, there are a plurality of stators, a plurality of rotors and a plurality of chambers.
 4. The colloid mill of claim 1 wherein one portion of said shaft is journaled for rotation and the portion of said shaft within said chamber extends to a free extremity thereof.
 5. The colloid mill of claim 1 wherein said slots include a first series of slots extending from a point adjacent to the outer periphery of said conical surface of said stator to a point adjacent to the inner aperture of said conical surface of said stator.
 6. A colloid mill comprising a casing disposed along an axis, a shaft disposed for rotation along said axis within said casing, at least a stator disposed about said shaft, said stator defining a re-entrant conical surface of revolution, said surface having therein grooves, at least a rotor keyed to said shaft for rotation therewith, said rotor having spaced blades, the outer edges of said blades being disposed in a conical surface of revolution, said conical surface of any stator and said conical surface of any rotor being adjacent, rotation of rotor causing refinement of colloid particles in a fluid passing from an inlet at one extremity of said shaft through at least a chamber defined by said stator and within which said rotor rotates, between said conical surfaces and through an outlet that is disposed in an axis perpendicular to the axis of said shaft, one of said series of said grooves extending from a T-head medially located between the outer periphery of said conical surface of said stator and the inner aperture of said conical surface of said stator to a point communicating with said inner aperture of said stator.
 7. The colloid mill of claim 1 including an inlet ring defining said inlet, a stator ring defining said reentrant conical surface and an outlet ring defining said outlet, the outer peripheries of said inlet ring, said stator ring, and said outlet ring being of like circular cross section and being registered to define an outer cylinder.
 8. A colloid mill comprising a casing disposed along an axis, said casing including a plurality of aligned rings, a shaft disposed for rotation along said axis within said casing, one of said rings defining a stator disposed about said shaft, said stator defining a re-entrant conical surface of revolution, and a re-entrant tubular surface of revolution in communication with eachother, said surfaces having therein grooves, a first series of said grooves extending from the forward periphery of said re-entrant conical surface to a medial portion thereof, a second series of said grooves extending from a medial portion of said re-entrant conical surface to the rearward periphery thereof, said first series of said grooves and said second series of said grooves being isolated from eachother, at least a rotor keyed to said shaft for rotation therewith, said rotor having spaced blades, the outer edges of said blades being disposed in a conical surface of revolution, said conical surface of any stator and said conical surface of any rotor being adjacent, another of said rings defining an inlet and another of said rings Defining an outlet, rotation of rotor causing refinement of colloid particles in a fluid passing from said inlet at one extremity of said shaft through at least a chamber defined by said stator and within which said rotor rotates, between said conical surfaces and through said outlet.
 9. The colloid mill of claim 8 wherein said conical surface of said stator and said conical surface of said rotor are spaced at most 0.01 inch from each other.
 10. The colloid mill of claim 8 wherein, in sequence, there are a plurality of stators, a plurality of rotors and a plurality of chambers.
 11. The colloid mill of claim 8 wherein one portion of said shaft is journaled for rotation and the portion of said shaft within said chamber extends to a free extremity thereof.
 12. The colloid mill of claim 8 wherein said slots include a first series of slots extending from a point adjacent to the outer periphery of said conical surface of said stator to a point adjacent to the inner aperture of said conical surface of said stator.
 13. A colloid mill comprising a casing disposed along an axis, said casing including a plurality of aligned rings a shaft disposed for rotation along said axis within said casing, one of said rings defining a stator disposed about said shaft, said stator defining a re-entrant conical surface of revolution, said surface having therein grooves, at least a rotor keyed to said shaft for rotation therewith, said rotor having spaced blades, the outer edges of said blades being disposed in a conical surface of revolution, said conical surface of any stator and said conical surface of any rotor being adjacent, another of said rings defining an inlet and another of said rings defining an outlet, rotation of rotor causing refinement of colloid particles in a fluid passing form said inlet at one extremity of said shaft through at least a chamber defined by said stator and within which said rotor rotates, between said conical surfaces and through said outlet, one of said series of said grooves extending from a T-head medially located between the outer periphery of said conical surface of said stator and the inner aperture of said conical surface of said stator to a point communicating with said inner aperture of said stator.
 14. A colloid mill comprising a casing disposed along an axis, said casing including a plurality of aligned rings, a shaft disposed for rotation along said axis within said casing, a plurality of said rings defining a plurality of stators disposed about said shaft, said stators defining reentrant conical surfaces of revolution, and re-entrant tubular surfaces of revolution said surfaces each having therein grooves, a first series of said grooves extending from the forward periphery of one of said re-entrant conical surfaces to a medial portion thereof, a second series of said grooves extending from a medial portion of said one of said re-entrant conical surfaces to the rearward periphery thereof, said first series of said grooves and said second series of said grooves being isolated from eachother, a plurality of rotors keyed to said shaft for rotation therewith, each said rotor having spaced blades, the outer edges of said blades being disposed in a conical surface of revolution, said conical surface of any stator and said conical surface of any rotor being adjacent, another of said rings defining an inlet and another of said rings defining an outlet, rotation of rotor causing refinement of colloid particles in a fluid passing form said inlet at one extremity of said shaft through at least a chamber defined by said stator and within which said rotor rotates, between said conical surfaces and through said outlet said conical surface of said stator and said conical surface of said rotor are spaced at most.01 inch form each other, one portion of said shaft being journaled for rotation and the portions of said shaft keyed to said rotors extending to a free extremity thereof.
 15. The colloid mill of claim 14 wherein said sloTs include a first series of slots extending from a point adjacent to the outer periphery of said conical surface of said stator to a point adjacent to the inner aperture of said conical surface of said stator.
 16. A colloid mill comprising a casing disposed along an axis, said casing including a plurality of aligned rings, a shaft disposed for rotation along said axis within said casing, a plurality of said rings defining a plurality of stators disposed about said shaft, said stators defining re-entrant conical surfaces of revolution, said surfaces each having therein grooves, a plurality of rotors keyed to said shaft for rotation therewith each said rotor having spaced blades, the outer edges of said blades being disposed in a conical surface of revolution, said conical surface of any stator and said conical surface of any rotor being adjacent, another of said rings defining an inlet and another of said rings defining an outlet, rotation of rotor causing refinement of colloid particles in a fluid passing from said inlet at one extremity of said shaft through at least a chamber defined by said stator and within which said rotor rotates, between said conical surfaces and through said outlet said conical surface of said stator and said conical surface of said rotor are spaced at most .01 inch from eachother, one portion of said shaft being journaled for rotation and the portions of said shaft keyed to said rotors extending to a free extremity thereof, one of said series of said grooves extending from a T-head medially located between the outer periphery of said conical surface of said stator and the inner aperature of said conical surface of said stator to a point communicating with said inner aperture of said stator. 